With development of communications technologies, currently many devices support a multi-task system, that is, a device may run multiple application programs at the same time, and one application program may have one or more threads, each of which is referred to as a task. Multiple tasks usually include a foreground task and a background task. The foreground task refers to a task that requires user interaction, that is, an operation input by a user needs to be received during execution of the foreground task. The background task refers to a task that does not require user interaction, that is, an operation input by a user does not need to be received during execution of the background task. Because the background task does not require user interaction, the background task is generally not a user-sensitive task, or the background task is not of user concern. In other words, some background tasks do not need to be executed. However, the background tasks are continually executed in the background of a system, and continuously consume power of a device. It can be seen that, currently a device may suffer from great power consumption and power loss.